For mammals, detecting heat is a natural sense which brings little to no discomfort. However, noxious heat is a thermal stimulation received and interpreted as harmful to the body, and can lead to chronic pain.
Noxious heat stimuli detection can be understood through nociceptor function. Nociceptors are how pain is felt: these peripheral sensory neurons have nerve endings in places like skin, known as cutaneous nociceptors, which detect noxious external stimuli like heat. From these nerve endings in the skin, once an acceptable heat limit is exceeded, nociceptors transduct noxious thermal stimuli into electrical signals which conduct action potentials along the respective axon fibers to the central nervous system (Dubin et. al, 2010). On a broad scale, signals from activated cutaneous nociceptor nerve endings travel to respective cell bodies in the dorsal root ganglia, and from the spinal cord transmit pain
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According to the 2010 paper by Dubin et. al, microneurography recordings in peripheral nerve fibers revealed that A - axon fibers are myelinated and quickly send action potentials to travel towards the central system (acute pain), while C - axon fibers are non-myelinated and send slower action potentials (extended pain) (Dubin et.al, 2010). According to Basbaum et. al 2009, when neurons were taken from dissociated DRG and cultured, both A and C fiber nociceptors had noxious heat thresholds of 43 C. Furthermore, by cloning the capsaicin receptor: when 43 C heat thresholds were exceeded by capsaicin, its respective heat receptor called TRPV1 was activated and caused subsequent depolarization of A and C fiber nociceptors, leading to painful sensation (Basbaum et. al,
Our results provide the first demonstration that GABAA but not GABA B receptor–selective agonists reverse the thermal hyperalgesia produced by spinal cord injury. In parallel, we demonstrate that in spinal cord injury similar to peripheral nerve injury, GABAA and GABAB receptor agonists reduce cold and tactile allodynia and mechanical hyperalgesia. In addition, our studies used a sensitive, reproducible test of motor function to compare the antiallodynic, antihyperalgesic, and motor effects of GABA receptor agonists. The data suggest that GABAA agonists may be efficacious in the treatment of neuropathic pain with thermal hyperalgesia without sensory or motor side effects.
Each sensation has its own neuronal receptor, such as: “mechanosensation, thermosensation, vibration, joint position, chemosensation, and electrosensation.” Oaklander then discusses “nocifensive sensations,” or senses that defend us from danger, such as pain and itch. These sensations trigger reflexes and strong movements. However, something that is often left undetected is chronic neuropathic pain, which can cause nerve damage. Shingles is a result of chronic neuropathic pain.
The most common and well described pain transmission is “gate control theory of pain”. This theory was first proposed by Melzack and Wall in 1965 whereby they used the analogy of gate to explain the inhibition of pain which exists within the dorsal horn of the spinal cord. For instance, when tissue damage occurs, substances such as prostaglandin, serotonin, histamine and bradykinin are released from the injured cell. Individual usually consume or apply pain medications such as NSAIDs whereby these medications will cause electrical nerve impulse at the end of the sensory nerve fiber via nociceptor. Nociceptor is a pain receptor that is commonly found in the skin, cornea of eye and organ of motion such as muscles and ligaments. These nerve impulses
Have you ever wondered why when you stub your toe on the chair in the living room, it helps tremendously to yell out an expletive or two and vigorously rub the area? I may not be able to discuss the basis for such language in this paper, but we will explore the analgesic response to rubbing that toe, in addition to the mechanism of pain and alternative treatments such as acupuncture and transcutaneous electrical nerve stimulation.
Since the first report on the success of acupuncture anesthesia in 1970s, much attention has been attracted to the effectiveness of acupuncture therapy worldwide. Analgesia is one of the most important effects of acupuncture. Generally, mechanisms of acupuncture analgesia contain mechanisms of acupuncture anesthesia, but the latter does not represent the entirety of acupuncture analgesia. This is because acupuncture not only treats acute or transient pain, but also chronic or persistent pain resulted from inflammations or other causes. Clinically, the pain usually occurs prior to acupuncture, either needling or moxibustion can be used for treatment. For acupuncture anesthesia, an induction period of acupuncture is required prior to the surgery and only needling or acupressure may be applied. In addition, the surgical pain pertains to the category of acute pain. However, most modern studies on mechanisms of acupuncture analgesia are conducted focusing on the mechanisms of acupuncture anesthesia. In the following discussion, we will first outlook those studies on acupuncture anesthesia, then provide a complementary explanation on mechanisms of clinical acupuncture analgesia, and finally analyze their implications in improving results of clinical analgesia. Primarily, mechanisms of acupuncture anesthesia or analgesia include two closely associated aspects: neural and humoral mechanisms [27].
Some people say that animals don't have feelings. Of course they do. Especially the feeling of pain. Everything does. Imagine being tied up with ropes or hanging from a metal device, and having drain cleaner poured down your throat.?
‘“It’s not that it makes you more intelligent,” says Phoebe, a history student. “It’s just that it helps you work. You can study for longer. You don’t get distracted. You’re actually happy to go to the library and you don’t even want to stop for lunch. And then it’s like 7pm, and you’re still, ‘Actually, you know what? I could do another hour.’” (Cadwalladr)
Circumcision, the removal of the foreskin over the penis, was long thought to be a painless experience for an infant and was treated accordingly with little or no anesthesia. Most of the times during the surgical procedure, the babies cry very forcefully. This was for a long time thought to be normal and healthy. Other times, they lie still without making a sound from either shock or the act of passing out from the pain (1). This unresponsiveness was always thought to be from undeveloped pain receptors, or Nociceptors in the Somatosensory system (2) . These pain receptors send information to the spinal cord, then to the brain stem, thalamus, and somatosensory cortex. Modulation can occur through these pathways by way of suppression using large mechanosensitive fibers that enter the spinal cord or by endorphine release. This modulation involves changing the information about the pain to lessen the perception of its magnitude.
The gate control theory of pain states that non-painful input closes the "gates" to painful input, which prevents pain sensation from traveling to the central nervous system. Stimulation by non-noxious input is able to suppress pain (Melzack). The gate control theory of pain asserts that non-painful input closes the "gates" to painful input, which prevents pain sensation from traveling to the central nervous system. The human brain is the key component in the sensation of pain.
Peripheral and central mechanisms involving nerve lesions and their input are substantial when perceiving phantom pain. Due to the impairment of peripheral nerves in the process of amputation, regenerative sprouting of damaged axons occurs and the activity rate of inflamed C-fibres and demyelinated A-fibres spontaneously increases (Flor, 2002). As a consequence of this nerve injury, a neuroma, which is a mass of pruned and tangled axons, may form in the residual limb producing abnormal (ectopic) activity (Katz, 1992). Flor, Nikolajsen and Jenson (2006) proposed that ectopic discharge from a neuroma in the stump illustrates abnormal afferent input to the spinal cord, which is a possible mechanism for unpro...
The most common is the mysterious flames. This is where a victim will just begin to emit flames from their body. Some victims claim they feel heat while others don’t. The second feature is the mysterious smoke in which a victim will begin to give off smoke from their bodies.
Burns are caused by many different factors. Heat burns are caused by fire, steam, hot objects, electricity, ultraviolet rays and hot liquids (Living With Burn Trauma). According to “Prevention,” an online article, the “Leading causes of fire and burn death and injury for older adults are smoking, cooking, scalds, electrical, and heating.” When one is burned, a instinct called “fight or flight” catalyzes. “Fight or Flight” causes one’s breathing and pulse to increase. When this happens, their adrenal glands release a hormone that causes pain to diminish causing some to vaguely remember their accident (Living With Burn Trauma). Many times because a victim begins to breathe rapidly, they can experience respiratory complications from the burns often resulting in respiratory failure (“First Aid and Emergencies”).
The parasympathetic nervous system does the opposite and brings the body back to normal. Sensory neurons are unipolar in shape and there are two types based on where the sensory neurons originate. Somatic sensory neurons are located in the skin skeletal muscles and joints bringing information to the CNS. It is made up of nerves that connect to skin, sensory organs, and skeletal muscles. One sensory neuron, photoreceptors in the eye, sense light. The neural impulses are then transmitted down the axons of the sensory neurons to the brain, where the brain then interprets what that input means. PNS plays a role in regulating blood pressure, thirst, and body temperature. Thermoreceptors in the skin help the body sense temperature. Motor neurons are completely different than sensory neurons, because they receive a signal from the central nervous system and tell responsive tissues what to do. Though most often associated with controlling muscle movement they also signal the glandular tissues and control secretion of various substances like gastric juices and saliva. Visceral sensory neurons give information to the CNS but not on a conscious level. Some internal organs that need regulating, but not at a conscious level are gallbladder, liver, kidney, and
At this moment, millions of animals know cold cages in laboratories as home, but why? Some of these animals are subjects for medical research purposes, while others are used out of pure curiosity and to test different products. The majority of these animals are used in painful experiments and are left in agony. While many of them die, a few animals survive, but these unfortunate ones wish they could be put out of their misery as well. Although scientists have resources they could use to lower the pain each animal endures and even alternatives for their test subjects, millions of innocent creatures are still suffering.
"An aspirin a day keeps the doctor away." Although this saying can be true, it is not only aspirin that can cure the pains of life, but also several other types of analgesics. There are a wide variety of analgesics. More commonly known as painkillers. The narcotic analgesics act on the central nervous system and change the user's perception; they are more often used for severe pain and can make the user develop an addiction. The nonnarcotic analgesics, known as over the counter or OTC, work at the site of the pain. These do not create tolerance or dependence and do not vary the user's perception. OTC's are more commonly used everyday to treat mild pain.